Bsi bs en 60695 1 21 2016

BS EN 60695-1-21:2016 BSI Standards Publication Fire hazard testing Part 1-21: Guidance for assessing the fire hazard of electrotechnical products — Ignitability — Summary and relevance of test methods BRITISH STANDARD BS EN 60695-1-21:2016 National foreword This British Standard is the UK implementation of EN 60695-1-21:2016 It is identical to IEC 60695-1-21:2016 It supersedes PD IEC/TR 60695-1-21:2008 which is withdrawn The UK participation in its preparation was entrusted to Technical Committee GEL/89, Fire hazard testing A list of organizations represented on this committee can be obtained on request to its secretary This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © The British Standards Institution 2016 Published by BSI Standards Limited 2016 ISBN 978 580 87360 ICS 13.220.40; 29.020 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2016 Amendments/corrigenda issued since publication Date Text affected BS EN 60695-1-21:2016 EUROPEAN STANDARD EN 60695-1-21 NORME EUROPÉENNE EUROPÄISCHE NORM November 2016 ICS 29.020; 13.220.40 English Version Fire hazard testing - Part 1-21: Guidance for assessing the fire hazard of electrotechnical products - Ignitability - Summary and relevance of test methods (IEC 60695-1-21:2016) Essais relatifs aux risques du feu - Partie 1-21: Lignes directrices pour l'évaluation des risques du feu des produits électrotechniques - Allumabilité - Résumé et pertinence des méthodes d'essais (IEC 60695-1-21:2016) Prüfungen zur Beurteilung der Brandgefahr - Teil 1-21: Anleitung zur Beurteilung der Brandgefahr von elektrotechnischen Erzeugnissen - Entzündbarkeit Zusammenfassung und Bedeutung der Prüfverfahren (IEC 60695-1-21:2016) This European Standard was approved by CENELEC on 2016-10-12 CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members Ref No EN 60695-1-21:2016 E BS EN 60695-1-21:2016 EN 60695-1-21:2016 European foreword The text of document 89/1336/FDIS, future edition of IEC 60695-1-21, prepared by IEC/TC 89 "Fire hazard testing" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 60695-1-21:2016 The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2017-07-12 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2019-10-12 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights Endorsement notice The text of the International Standard IEC 60695-1-21:2016 was approved by CENELEC as a European Standard without any modification In the official version, for Bibliography, the following notes have to be added for the standards indicated: ISO 11357 (Series) NOTE Harmonized as EN ISO 11357 (Series) ISO 4589-1:1996 NOTE Harmonized as EN ISO 4589-1:1999 ISO 4589-2:1996 NOTE Harmonized as EN ISO 4589-2:1999 ISO 4589-3:1996 NOTE Harmonized as EN ISO 4589-3:1999 BS EN 60695-1-21:2016 EN 60695-1-21:2016 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies NOTE When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies NOTE Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu Publication IEC 60695-1-20 Year - IEC 60695-1-30 - IEC 60695-4 2012 IEC Guide 104 - ISO 13943 ISO/IEC Guide 51 2008 - Title Fire hazard testing - Part 1-20: Guidance for assessing the fire hazard of electrotechnical products - Ignitability General guidance Fire hazard testing Part 1-30: Guidance for assessing the fire hazard of electrotechnical products - Preselection testing process - General guidelines Fire hazard testing Part 4: Terminology concerning fire tests for electrotechnical products The preparation of safety publications and the use of basic safety publications and group safety publications Fire safety - Vocabulary Safety aspects - Guidelines for their inclusion in standards EN/HD EN 60695-1-20 Year - EN 60695-1-30 - EN 60695-4 2012 - - EN ISO 13943 - 2010 - BS EN 60695-1-21:2016 –2– IEC 60695-1-21:2016  IEC 2016 CONTENTS FOREWORD INTRODUCTION Scope Normative references Terms and definitions Summary of published test methods 12 4.1 General 12 4.2 Tests using heated air or electrical heating 12 4.2.1 Determination of ignition temperature using a hot-air furnace, ISO 871 12 4.2.2 Differential scanning calorimetry (DSC), ISO 11357 [1] 13 4.3 Tests using radiant heat 14 4.3.1 Heat release rate – Cone calorimeter method, ISO 5660-1 [4] 14 4.3.2 Heat release of insulating liquids, IEC TS 60695-8-3 [5] 15 4.3.3 Standard test method for determining material ignition and flame spread properties, ASTM E 1321 [6] 16 4.3.4 Determination of the characteristic heat flux for ignition from a noncontacting flame source, IEC TS 60695-11-11 [7] 17 4.4 Oxygen index tests 17 4.4.1 Oxygen index – Ambient temperature test, ISO 4589-2 [8] 17 4.4.2 Oxygen index – Elevated temperature test, ISO 4589-3 [10] 18 4.5 Glowing/hot-wire based test methods 20 4.5.1 Glow wire tests, IEC 60695-2-11 [14], IEC 60695-2-12 [15] and IEC 60695-2-13 [16] 20 4.5.2 Hot wire coil ignitability test, IEC 60695-2-20 and ASTM D 3874 [17] 22 4.6 Flame tests 23 4.6.1 Needle flame test, IEC 60695-11-5 [18] 23 4.6.2 50 W Horizontal and vertical flame test methods, IEC 60695-11-10 [19] 500 W flame test methods, IEC 60695-11-20 [20] 24 4.6.3 kW nominal pre-mixed flame, IEC 60695-11-2 [23] 25 4.6.4 Vertical and 60° tests for aircraft components, FAR 25 [25] 25 4.7 Tests using an electrical arc 26 4.7.1 Tracking index tests, IEC 60112 [26], ASTM D 3638 [27] 26 4.7.2 High-Current Arc Ignition (HAI), UL 746A – Sec 32 [30] 28 4.7.3 High-voltage arc resistance to ignition (HVAR), UL 746A – Sec 33 [31] 28 Annex A (informative) Applicability of test methods 30 A.1 Applicability of test methods 30 Bibliography 32 Table – Main differences between IEC 60112 and ASTM D 3638 27 Table A.1 – Applicability of test methods (1 of 2) 30 BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 –3– INTERNATIONAL ELECTROTECHNICAL COMMISSION FIRE HAZARD TESTING – Part 1-21: Guidance for assessing the fire hazard of electrotechnical products – Ignitability – Summary and relevance of test methods FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees) The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”) Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work International, governmental and nongovernmental organizations liaising with the IEC also participate in this preparation IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter 5) IEC itself does not provide any attestation of conformity Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity IEC is not responsible for any services carried out by independent certification bodies 6) All users should ensure that they have the latest edition of this publication 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications 8) Attention is drawn to the Normative references cited in this publication Use of the referenced publications is indispensable for the correct application of this publication 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights IEC shall not be held responsible for identifying any or all such patent rights International Standard IEC 60695-1-21 has been prepared by IEC technical committee 89: Fire hazard testing The text of this standard is based on the following documents: FDIS Report on voting 89/1336/FDIS 89/1339/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table This publication has been drafted in accordance with the ISO/IEC Directives, Part BS EN 60695-1-21:2016 –4– IEC 60695-1-21:2016  IEC 2016 It has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC Guide 51 This first edition of IEC 60695-1-21 cancels and replaces the IEC TR 60695-1-21 published in 2008 It constitutes a technical revision first edition of This edition includes the following significant technical changes with respect to the previous edition: a) Change from a TR to an international standard; b) Modified Introduction; c) Modified Scope; d) Updated normative references; e) Updated terms and definitions; f) Updates and new text in Clause 4; g) Addition of text concerning ASTM D 3638; h) Updates to Annex A; i) Updates to the bibliography A list of all the parts in the IEC 60695 series, under the general title Fire hazard testing, can be found on the IEC website The IEC 60695-1 series, under the general title Fire hazard testing, consists of the following parts: Part 1-10: Guidance for assessing the fire hazard of electrotechnical products – General guidelines Part 1-11: Guidance for assessing the fire hazard of electrotechnical products – Fire hazard assessment Part 1-12: Guidance for assessing the fire hazard of electrotechnical products – Fire safety engineering Part 1-20: Guidance for assessing the fire hazard of electrotechnical products – Ignitability – General guidance Part 1-21: Guidance for assessing the fire hazard of electrotechnical products – Ignitability – Summary and relevance of test methods Part 1-30: Guidance for assessing the fire hazard of electrotechnical products – Preselection testing procedures – General guidelines Part 1-40: Guidance for assessing the fire hazard of electrotechnical products – Insulating liquids The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication At this date, the publication will be • • • • reconfirmed, withdrawn, replaced by a revised edition, or amended BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 –5– INTRODUCTION Fires are responsible for creating hazards to life and property as a result of the generation of heat (thermal hazard), and also as a result of the production of toxic effluent, corrosive effluent and smoke (non-thermal hazard) Fires start with ignition and then can grow, leading in some cases to flash-over and a fully developed fire Ignition resistance is therefore one of the most important parameters of a material to be considered in the assessment of fire hazard If there is no ignition, there is no fire For most materials (other than metals and some other elements), ignition occurs in the gas phase Ignition occurs when combustible vapour, mixed with air, reaches a high enough temperature for exothermic oxidation reactions to rapidly propagate The ease of ignition is a function of the chemical nature of the vapour, the fuel/air ratio and the temperature In the case of liquids, the combustible vapour is produced by vaporization of the liquid, and the vaporization process is dependent on the temperature and chemical composition of the liquid In the case of solids, the combustible vapour is produced by pyrolysis when the temperature of the solid is sufficiently high The vaporization process is dependent on the temperature and chemical composition of the solid, and also on the thickness, density, specific heat, and thermal conductivity of the solid The ease of ignition of a test specimen depends on many variables Factors that need to be considered for the assessment of ignitability are: a) the geometry of the test specimen, including thickness and the presence of edges, corners or joints; b) the surface orientation; c) the rate and direction of air flow; d) the nature and position of the ignition source; e) the magnitude and position of any external heat flux; and f) whether the combustible material is a solid or a liquid In the design of an electrotechnical product the risk of fire and the potential hazards associated with fire need to be considered In this respect the objective of component, circuit and equipment design, as well as the choice of materials, is to reduce the risk of fire to a tolerable level even in the event of reasonably foreseeable (mis)use, malfunction or failure Fires involving electrotechnical products can also be initiated from external non-electrical sources Considerations of this nature are dealt with in an overall fire hazard assessment The aim of the IEC 60695 series of standards is to save lives and property by reducing the number of fires or reducing the consequences of the fire This can be accomplished by: • trying to prevent ignition caused by an electrically energised component part and, in the event of ignition, to confine any resulting fire within the bounds of the enclosure of the electrotechnical product • trying to minimise flame spread beyond the product’s enclosure and to minimise the harmful effects of fire effluents including heat, smoke, and toxic or corrosive combustion products For these reasons there are many tests used to evaluate the ignitability of electrotechnical products and of the materials used in their construction This part of IEC 60695 describes ignitability test methods in common use to assess electrotechnical products, or materials used in electrotechnical products It also includes test methods in which, by design, BS EN 60695-1-21:2016 –6– IEC 60695-1-21:2016  IEC 2016 ignitability is a significant quantifiable characteristic It forms part of the IEC 60695-1 series, which gives guidance to product committees wishing to incorporate fire hazard test methods in product standards BS EN 60695-1-21:2016 – 22 – 4.5.1.3 IEC 60695-1-21:2016  IEC 2016 Glow-wire ignition temperature (GWIT) test method for materials, IEC 60695-2-13 [16] 4.5.1.3.1 Purpose and principle The glow-wire is a specified loop of resistance wire, which is electrically heated to a specified temperature The test apparatus is described in IEC 60695-2-10 [13] The purpose of IEC 60695-2-13 is to determine the glow-wire ignitability index (GWIT) of solid electrical insulating materials and other solid materials The GWIT is the minimum temperature at which ignition will take place 4.5.1.3.2 Test specimens The dimensions of the test specimens are ≥ 60 mm × ≥ 60 mm × a preferred value of thickness They can be manufactured by compression moulding, injection moulding or casting, or cut from sheets or parts of end-products 4.5.1.3.3 Test method The tip of the heated glow-wire is brought into contact with the vertically mounted test specimen for a specific period of time and a range of observations and measurements made, dependent upon the particular test procedure By repeated tests with different test temperatures of the glow-wire, using a new test specimen each time, the GWIT of the material under test is established 4.5.1.3.4 Repeatability and reproducibility No data are known to be available 4.5.1.3.5 Relevance of test data This test is a materials test carried out on a series of standard test specimens The data obtained can then be used in a preselection process to judge the ability of materials to meet the requirements of IEC 60695-2-11, the glow-wire flammability test method for end products The test method is not valid for determining the ignitability, fire behaviour, or fire hazard of complete items of equipment, since the dimensions of the insulating systems or combustible parts, the design and heat transfer to adjacent metallic or non-metallic parts, etc., greatly influence the flammability of the materials used therein As an outcome of conducting a fire hazard assessment, an appropriate series of preselection flammability and ignition tests may permit reduced end product testing (see IEC 60695-1-30) 4.5.2 4.5.2.1 Hot wire coil ignitability test, IEC 60695-2-20 and ASTM D 3874 [17] Purpose and principle This test method is intended, in a preliminary fashion, to differentiate materials with respect to their resistance to ignition caused by their proximity to electrically heated wires and other heat sources Under certain normal (as well as abnormal) operations of electrical equipment, insulating materials may be in close proximity of a heated electrical source such as a motor, a conductor in an overcurrent state, or resistive heating source If the intensity and/or duration of the exposure to these sources is severe, the insulating material may ignite _ Withdrawn in 2007 BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 4.5.2.2 – 23 – Test specimen The test specimen consists of a bar specimen 13,0 mm ± 0,5 mm at the thickness to be evaluated 4.5.2.3 measuring 125 mm ± mm by Test method In this test method, the test specimen, with the center portion wrapped with a coil of heater wire, is supported horizontally at both ends The circuit is then energized by applying a fixed power density to the heater wire, which rapidly heats up The behaviour of the test specimen is observed until one of the following happens: a) the material under test ignites, b) the material under test melts, or c) 120 s of exposure have elapsed without the occurrence of ignition or melting The time to ignition and the time to melt-through, as applicable, are recorded 4.5.2.4 Repeatability and reproducibility There are currently no published data available ASTM D 3874 states: “It is likely that, when care is taken to adhere to this test method, the average determined will fall within plus or minus 15 % of the value obtained by an interlaboratory evaluation.” However, the IEC test was withdrawn in 2007 because of unsatisfactory repeatability and reproducibility 4.5.2.5 Relevance of test data This test method is used for preselection of materials, for quality control and product evaluation The resultant data have been used for determining the suitability of polymeric materials intended for use in electrical equipment when in direct contact or within 0,8 mm of possible ignition sources 4.6 Flame tests 4.6.1 4.6.1.1 Needle flame test, IEC 60695-11-5 [18] Purpose and principle The needle flame test, IEC 60695-11-5, simulates the effect of a small flame which may result from fault conditions, in order to assess the fire hazard 4.6.1.2 Test specimen The test specimen is a complete equipment, sub-assembly or component 4.6.1.3 Test method A 12 mm high butane test flame is applied to that part of the test specimen most likely to be affected by flames for a specified duration A specified layer is placed underneath the test specimen to evaluate the possibility of spread of fire During and after the application of the test flame the test specimen is observed for glowing, dripping particles and ignition 4.6.1.4 Repeatability and reproducibility No data are known to be available BS EN 60695-1-21:2016 – 24 – 4.6.1.5 IEC 60695-1-21:2016  IEC 2016 Relevance of test data The needle flame test is used to check the suitability of materials that may be affected by flames from insulating materials supporting live parts under conditions of an overheated electrical connection It can also be used to check materials that may require consequential testing (see 4.5.1.1.5) In some cases a part that would normally be required to meet IEC 60695-2-11 may have dimensions incompatible with the glow wire test apparatus Should this situation occur, product committees may use the needle flame test IEC 60695-11-5 4.6.2 4.6.2.1 50 W horizontal and vertical flame test methods, IEC 60695-11-10 [19]; 500 W flame test methods, IEC 60695-11-20 [20] Purpose and principle IEC 60695-11-10 is a test method using a 50 W flame IEC 60695-11-20 is a test method using a 500 W flame These test methods refer to solid electrical insulating materials and are intended to serve as a preliminary indication of their behaviour when exposed to a flame ignition source The results make it possible to check the constancy of the characteristics of a material and provide an indication of the progress in the development of insulating materials and a relative comparison and classification of various materials 4.6.2.2 Test specimen In both test methods the test specimen is 125 mm long, 13 mm wide, and up to 13 mm thick 4.6.2.3 Test method These tests involve applying a flame ignition source to a horizontal or vertical test specimen and measuring the burned length or surface spread of flame rate NOTE The apparatus for producing the 50 W flame is described in IEC 60695-11-4 [21] The apparatus for producing the 500 W flame is described in IEC 60695-11-3 [22] 4.6.2.4 Repeatability and reproducibility Data are available in IEC 60695-11-10:2013, Annexes A and B, and IEC 60695-11-20:2015, Annex A 4.6.2.5 Relevance of test data This test is a materials test carried out on a series of standard test specimens The data obtained can then be used in a preselection process to judge the ability of materials to meet the many flammability requirements for end products The test method is not valid for determining the flammability, fire behaviour, or fire hazard of complete items of equipment, since the dimensions of the insulating systems or combustible parts, the design and heat transfer to adjacent metallic or non-metallic parts, etc., greatly influence the flammability of the materials used therein As an outcome of conducting a fire hazard assessment, an appropriate series of preselection flammability and ignition tests may permit reduced end product testing (see IEC 60695-1-30) BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 4.6.3 4.6.3.1 – 25 – kW nominal pre-mixed flame, IEC 60695-11-2 [23] Purpose and principle IEC 60695-11-2 provides detailed requirements for the production of a kW nominal, propane based pre-mixed type test flame 4.6.3.2 Test specimen The test flame can be used to test electrotechnical equipment, sub-assemblies and components and solid electrical insulating materials or other combustible materials Test specimen details are described in the relevant standards that use this test flame 4.6.3.3 Test method Examples of appropriate test arrangements are given in Annex B of IEC 60695-11-2:2013 Numerous tests use this flame ignition source For details the relevant test method should be consulted When used for testing equipment, unless otherwise stated in the relevant specification, the recommended distance from the top of the burner tube to the point on the surface of the test specimen is approximately 100 mm and the burner is fixed in position during the test When used for testing strips of materials, where the operator may move the flame during the test to follow the distorting or burning test specimen, the tip of the blue cone in the flame should be as close as possible without touching the test specimen 4.6.3.4 Confirmation of the test flame Confirmation of the test flame is carried out by measuring the time taken for a defined copper block to increase in temperature by a defined amount 4.6.3.5 Relevance of test data This kW, high intensity, pre-mixed test flame is very widely used to simulate the reaction to fire of end-products, components and materials to the direct impingement of a flame ignition source 4.6.4 4.6.4.1 Vertical and 60° tests for aircraft components, FAR 25 [25] Purpose and principle The requirements for electrical system components are given in FAR 25.869 (a) It states that insulation on electrical wires and electric cable installed in any area of an aeroplane fuselage shall be self-extinguishing when tested in accordance with a 60 ° Bunsen burner test described in Part I, Appendix F of FAR 25 The requirements for materials and parts used in the crew and passenger compartments are given in FAR 25.853 It states that electrical conduit shall be self-extinguishing when tested in accordance with a vertical Bunsen burner test described in Part I, Appendix F of FAR 25 4.6.4.2 Test specimen The test specimen for the vertical Bunsen burner test is at least 50 mm wide and 305 mm long, unless the actual size used in the airline is smaller The test specimen thickness is no thicker than the minimum thickness qualified for use in an airline The test specimen for the 60 ° Bunsen burner test is a length of wire or cable The gauge is the same as that used in the airline BS EN 60695-1-21:2016 – 26 – 4.6.4.3 IEC 60695-1-21:2016  IEC 2016 Test method These tests involve applying an ignition source to a 60 ° or vertical test specimen The flame time, burned length, and flaming time of drippings, if any, are then measured or noted Electrical conduits are submitted to a 12 s application of flame Wire and cable products are submitted to a 30 s application of flame 4.6.4.4 Repeatability and reproducibility No data are known to be available 4.6.4.5 Relevance of test data These test methods are used for the preselection of materials, quality control and product evaluation for electrical wires, electrical cables and electrical conduit used in the aviation industry 4.7 Tests using an electrical arc 4.7.1 4.7.1.1 Tracking index tests, IEC 60112 [26], ASTM D 3638 [27] Purpose and principle Both IEC 60112 and ASTM D 3638 specify the method of test for the determination of the comparative tracking index (CTI) of solid insulating materials on pieces taken from parts of equipment and on plaques of material using alternating voltages IEC 60112 also specifies the method of test for the determination of the proof tracking index (PTI) The standards also provide for the determination of erosion when required For an overview of the main differences between IEC 60112 and ASTM D 3638, see Table 4.7.1.2 Test specimen For the IEC 60112 test method the test specimen should be flat, at least mm thick, and have an area sufficient to ensure that during the test no liquid flows over the edges of the test specimen The recommended minimum size is 20 mm × 20 mm For ASTM D 3638 a minimum thickness of 2,5 mm is to be used In case thinner samples are used, these plaques have to be stacked to the minimum thickness specified in both test standards 4.7.1.3 Test method The upper surface of the test specimen is supported in an approximately horizontal plane and subjected to an electrical stress via two platinum electrodes, mm apart, using an a.c voltage of between 100 V and 600 V The surface between the electrodes is subjected to a succession of drops of electrolyte either until an over-current device operates, or until ignition and a persistent flame occurs, or until the test period has elapsed The individual tests are of short duration (less than h) with up to 50 or 100 drops of about 20 mg of electrolyte falling at 30 s intervals The number of drops needed to cause failure usually increases with decreasing applied voltage and, below a critical value, tracking ceases to occur During the test, the specimen may also erode or soften, thereby allowing the electrodes to penetrate it If required, erosion is measured If a hole is formed, this is reported Table lists the main differences between IEC 60112 and ASTM D 3638 BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 – 27 – Table – Main differences between IEC 60112 and ASTM D 3638 Parameter Specimen thickness Electrolyte: Ammonium chloride (aq.) IEC 60112 ASTM D 3638 ≥ mm ≥ 2,5 mm Solution A (CTI and PTI) (CTI) (395 ± 5) Ω cm (385 ± 5) Ω cm Electrolyte: Ammonium chloride and alkyl naphthalene sulphonate (aq.) Solution B (CTI-M) (200 ± 5) Ω cm Not applicable NOTE more aggressive Length of the electrodes ≥ 12 mm The maximum voltage that does not cause ignition or tracking (conduction) with solution A Evaluation of test results for CTI ≥ 20 mm a) test specimens withstand 50 drops without failure, and The voltage which will cause failure by tracking (conduction) when the number of drops of contaminant required to cause failure is equal to 50 b) test specimens withstand 100 drops at 25 V lower Ignition of the specimen is not a failure criterion Result reported e.g as: “CTI 300” The test is done on specimens If the voltage, at which 100 drops can be applied without failure, is lower than the CTI – 25 V, then that voltage is written in parentheses along with the CTI value The average number of drops/voltage relation is plotted on a graph The CTI voltage is read from the graph where 50 drops cause failure Example: “CTI 300 (250)” Evaluation of test results for CTI-M Evaluation of test results for PTI 4.7.1.4 The same as for CTI, but with solution B Not applicable The same as for CTI part a) It is used as a pass or fail test at a voltage specified in an end product specification Not applicable Repeatability and reproducibility For IEC 60112 data are reported in IEC TR 62062:2002 [28] 4.7.1.5 Relevance of test data The test discriminates between materials with relatively poor resistance to tracking, and those with moderate or good resistance, for use in equipment which can be used under moist conditions The test is not a good indicator of a material’s ability to resist ignition from an arcing source as a primary failure mode The method is set up to create accelerated conditions for the evaluation of tracking as a primary failure mode However, these conditions not accurately reflect conditions under which an arc ignition would occur in the field While ignition of the specimen often occurs during this test, it is a secondary event to the developing (or completed) carbon track NOTE More severe tests of longer duration are required for the assessment of performance of materials for outdoor use, utilizing higher voltages and larger test specimens – see the inclined plane test, IEC 60587 [29] BS EN 60695-1-21:2016 – 28 – 4.7.2 4.7.2.1 IEC 60695-1-21:2016  IEC 2016 High-Current Arc Ignition (HAI), UL 746A – Sec 32 [30] Purpose and principle UL 746A – Sec 32 was developed to differentiate between solid insulating materials with regard to resistance to ignition from arcing electrical sources Under certain normal, as well as abnormal, operations of electrical equipment, insulating materials may be in the proximity of a source of arcing If the intensity and/or duration of the arcing are severe, the insulating material may ignite 4.7.2.2 Test specimen The test specimen consists of a bar sample measuring 125 mm ± mm by 13,0 mm ± 0,5 mm at the thickness to be evaluated 4.7.2.3 Test method Two electrodes, one a copper rod and the other a stainless steel rod, both at 45 º to the horizontal, are brought into contact on the surface of the test specimen The stainless steel electrode is capable of being removed to a distance that will break an arc and then brought back into contact to reinitiate the arc in a cyclic motion along its 45º axis At the initiation of the test, a 32,5 A circuit (power factor 0,5) is energized and the movable electrode is cycled at a rate of 40 arcs per minute until a flame is detected (or the specimen sustains 200 arcs without ignition) The test may also be run with the initial electrode contact 1,6 mm or 3,2 mm above the surface 4.7.2.4 Repeatability and reproducibility There are no currently published data available However, it is recognized that the following factors often contribute to a broad deviation in measured data; a) the occurrence of variable arc profiles due to asynchronous timing of AC frequency and arc initiation, b) deterioration of electrode tips during the test cycle, and c) lack of precise control of the moveable electrode A revised method that addresses these issues (and others) is currently under development in the United States 4.7.2.5 Relevance of test data These test methods are used for the preselection of materials, for quality control and product evaluation The resulting data have been used for determining the suitability of polymeric materials intended for use in electrical equipment when in direct contact, within 0,8 mm of non-arcing sources (such as single conductors or bus-bars), or within 12,7 mm of arcing sources (such as parts of opposite polarity) 4.7.3 4.7.3.1 High-voltage arc resistance to ignition (HVAR), UL 746A – Sec 33 [31] Purpose and principle UL746A – Sec 33 is used to differentiate between solid insulating materials with regard to resistance to ignition or the formation of a visible carbonized conducting path over the surface of the material when subjected to high voltage, low current arcing such as during the malfunction of certain high voltage power supplies in electrical equipment BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 4.7.3.2 – 29 – Test specimen The test specimen consists of a bar sample measuring 125 mm ± mm by 13,0 mm ± 0,5 mm at the thickness to be evaluated The test specimens are preconditioned for a minimum of 40 h at 23 ºC ± ºC and at 50 % ± % relative humidity 4.7.3.3 Test method Two electrodes, both at 45º to the horizontal, are placed 4,0 mm ± 0,1 mm apart on the surface of the test specimen At the initiation of the test, an initial circuit of 5,2 kV with a current limiter of 2,36 mA is utilized to create a continuous arc between the electrodes The test is continued for or until ignition occurs, or a hole forms in the test specimen 4.7.3.4 Repeatability and reproducibility No data are currently available 4.7.3.5 Relevance of test data These test methods are used for the preselection of materials, for quality control and product evaluation The resulting data have been found useful for determining the suitability of polymeric materials intended for use in electrical equipment when in direct contact or close proximity (0,8 mm to non-arcing or 12,7 mm to arcing) to uninsulated live parts Applicability of test methods         × Differential scanning calorimetry ISO 11357 Cone calorimeter method ISO 5660-1 Heat release of insulating liquids IEC 60695-8-3 Material ignition and flame spread test ASTM E 1321 ICHF from a flame source IEC/TS 60695-11-11 Oxygen index – Ambient temperature test ISO 4589-2 Oxygen index – Elevated temperature test ISO 4589-3 Glow-wire flammability test for end-products IEC 60695-2-11 4.2.2 4.3.1 4.3.2 4.3.3 4.3.4 4.4.1 4.4.2 4.5.1.1 Material test Hot-air furnace ISO 871 Test method 4.2.1 Subclause  × ×   The ignition source is a hot wire applied for 30 s This test is based on whether burning in air is sustained after ignition Temperature is a variable This test is based on whether burning is sustained after ignition Oxygen volume fraction is a variable This test measures ignition time as a function of the heat flux from a non-contacting flame This is used mainly to assess interior building materials This is a test for insulating liquids It is predominantly a heat release rate test, but time to ignition is measured This is predominantly a heat release rate test, but time to ignition is measured This measures a number of properties which affect ignitability This measures the flash-ignition temperature and spontaneousignition temperature of plastics Comments – 30 –  If the geometry is appropriate × × End-product test Table A.1 – Applicability of test methods (1 of 2) Table A.1 lists the test methods described in Clause and distinguishes between material tests and end-product tests A.1 Applicability of test methods Annex A (informative) BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016     Glow-wire ignitability test for materials IEC 60695-2-13 Hot wire coil ignitability test ASTM D3874 [IEC 60695-2-20, withdrawn] Needle flame test IEC 60695-11-5 50 W Horizontal and vertical flame test methods IEC 60695-11-10 4.5.1.3 4.5.2 4.6.1  High-voltage arc ignition (HVAR) test UL 746A – Sec 33 4.7.3 b PTI = Proof tracking index CTI = Comparative tracking index  High-current arc ignition (HAI) test UL 746A – Sec 32 4.7.2 a  Standard test method for comparative tracking index of electrical insulating materials ASTM D 3638 4.7.1 × Vertical and 60° tests for aircraft components FAR 25 – Part I – Appendix F 4.6.4 (CTI) a  kW nominal pre-mixed flame IEC 60695-11-2 4.6.3 Proof and comparative tracking indices of solid insulating materials IEC 60112  500 W flame test methods IEC 60695-11-20 4.6.2  Material test Glow-wire flammability test for materials IEC 60695-2-12 Test method 4.5.1.2 Subclause × × × (PTI) b   × ×  × × × End-product test Table A.1 (2 of 2) This is used to evaluate polymeric insulating materials This is used to evaluate polymeric insulating materials Flame ignition shall be reported Ignition which causes persistent flaming (burning for more than s) is a failure criterion in this test This is a test for aerospace electrical wires and cables The ignition source is a kW pre-mixed flame The ignition source is a 500 W pre-mixed flame The ignition source is a 50 W pre-mixed flame The ignition source is a small diffusion flame The ignition source is a hot wire coiled round the test specimen Heating is applied for up to 120 s The IEC test method, IEC 60695-2-20, was withdrawn because of poor repeatability and reproducibility The ignition source is a hot wire applied for 30 s The glow-wire ignitability index (GWIT) is determined The ignition source is a hot wire applied for 30 s The glow-wire flammability index (GWFI) is determined Comments BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 – 31 – BS EN 60695-1-21:2016 – 32 – IEC 60695-1-21:2016  IEC 2016 Bibliography [1] ISO 11357, Plastics – Differential scanning calorimetry (DSC) [2] SFPE Handbook of Fire Protection Engineering, National Fire Protection Association Press, Quincy, MA (USA), 1995, pp 1-103 to 1-106 [3] Haines, P J., Thermal methods of analysis, Blackie Academic & Professional, Glasgow, 1995 [4] ISO 5660-1:2015, Reaction-to-fire tests – Heat release, smoke production and mass loss rate – Part 1: Heat release rate (cone calorimeter method) [5] IEC TS 60695-8-3, Fire hazard testing – Part 8-3:Heat release – Heat release of insulating liquids used in electrotechnical products [6] ASTM E 1321, Standard Test Method for Determining Material Ignition and Flame Spread Properties [7] IEC TS 60695-11-11, Fire hazard testing – Part 11-11: Test flames – Determination of the ignition characteristic heat flux from a non-contacting flame source [8] ISO 4589-2:1996, Plastics – Determination of burning behaviour by oxygen index – Part 2: Ambient-temperature test [9] Fenimore and Martin, Modern Plastics, 43, p 141, 1966 [10] ISO 4589-3:1996, Plastics – Determination of burning behaviour by oxygen index – Part 3: Elevated-temperature test [11] Weil, Hirschler, Patel, Said and Shakir, Fire and Materials, 16(4), p 159, 1992 [12] ISO 4589-1, Plastics – Determination of burning behaviour by oxygen index – Part 1: Guidance [13] IEC 60695-2-10, Fire hazard testing – Part 2-10: Glowing/hot-wire based test methods – Glow-wire apparatus and common test procedure [14] IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods – Glow-wire flammability test method for end-products [15] IEC 60695-2-12, Fire hazard testing – Part 2-12: Glowing/hot-wire based test methods – Glow-wire flammability test method for materials [16] IEC 60695-2-13, Fire hazard testing – Part 2-13: Glowing/hot-wire based test methods – Glow-wire ignitability test method for materials [17] ASTM D 3874, Standard Test Method for Ignition of Materials by Hot Wire Sources [18] IEC 60695-11-5, Fire hazard testing – Part 11-5: Needle flame test [19] IEC 60695-11-10:2013, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical flame test method BS EN 60695-1-21:2016 IEC 60695-1-21:2016  IEC 2016 – 33 – [20] IEC 60695-11-20:2015, Fire hazard testing – Part 11-20: Test flames – 500 W flame test methods [21] IEC 60695-11-4, Fire hazard testing – Part 11-4: Test flames – 50 W flame – Apparatus and confirmational test method [22] IEC 60695-11-3, Fire hazard testing – Part 11-3: Test flames – 500 W flames – Apparatus and confirmational test methods [23] IEC 60695-11-2:2013, Fire hazard testing – Part 11-2: Test flames – kW pre-mixed flame test method [24] IEC 60695-11-40, Fire hazard testing – Part 11-40: Test flames – Confirmatory tests – Guidance [25] FAR 25, Federal Aviation Regulations – Airworthiness standards – Part 25: Transport category – Airplanes [26] IEC 60112, Method for the determination of the proof and the comparative tracking indices of solid insulating materials [27] ASTM D 3638, Standard Test Method for Comparative Tracking Index of Electrical Insulating Materials [28] IEC TR 62062:2002, Results of the Round Robin series of tests to evaluate proposed amendments to IEC 60112 [29] IEC 60587, Test method for evaluating resistance to tracking and erosion of electrical insulating materials used under severe ambient conditions [30] UL 746A – Sec 32, Standard for Polymeric Materials – Short Term Property Evaluations – Sec 43: High-current arc ignition test [31] UL 746A – Sec 33, Standard for Polymeric Materials – Short Term Property Evaluations – Sec 44: High-voltage arc ignition test [32] ISO 871:2006, Plastics – Determination of ignition temperature using a hot-air furnace This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and 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